U.S. patent number 9,890,874 [Application Number 15/036,680] was granted by the patent office on 2018-02-13 for multistage trim for control valves.
This patent grant is currently assigned to Nuovo Pignone Srl. The grantee listed for this patent is Nuovo Pignone Srl. Invention is credited to Lorenzo Bergamini, Vincenzo Pietanza.
United States Patent |
9,890,874 |
Bergamini , et al. |
February 13, 2018 |
Multistage trim for control valves
Abstract
A control valve comprising a cylindrical hollow trim defining an
inner bore extending along an axis between a first opening and a
second opening, the first opening defining an inlet of the valve,
the trim comprising a first outer cylinder extending along the axis
and comprising a first plurality of radial through holes defining
an outlet, a second cylinder, housed in the first cylinder and
coaxial, the second cylinder comprising a second plurality of
radial through holes, the holes of the first plurality being
smaller and in greater number than the holes of the second
plurality, for each hole of one of the first and second cylinders
the projection along a radial direction on the other of the first
and second cylinders being spaced from each hole of the other of
the first and second plurality a plug sized to fit inside the bore
and slidably movable along the axis.
Inventors: |
Bergamini; Lorenzo (Bari,
IT), Pietanza; Vincenzo (Florence, IT) |
Applicant: |
Name |
City |
State |
Country |
Type |
Nuovo Pignone Srl |
Florence |
N/A |
IT |
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Assignee: |
Nuovo Pignone Srl (Florence,
IT)
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Family
ID: |
50001107 |
Appl.
No.: |
15/036,680 |
Filed: |
November 14, 2014 |
PCT
Filed: |
November 14, 2014 |
PCT No.: |
PCT/EP2014/074571 |
371(c)(1),(2),(4) Date: |
May 13, 2016 |
PCT
Pub. No.: |
WO2015/071398 |
PCT
Pub. Date: |
May 21, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160281880 A1 |
Sep 29, 2016 |
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Foreign Application Priority Data
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Nov 15, 2013 [IT] |
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CO2013A0060 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K
47/08 (20130101); F16K 11/07 (20130101) |
Current International
Class: |
F16K
47/08 (20060101); F16K 11/07 (20060101) |
Field of
Search: |
;137/625.28,625.3,625.33,625.37,625.38 ;251/118 ;138/40,43 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1003727 |
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Jan 1977 |
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CA |
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2009209976 |
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Sep 2009 |
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JP |
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2012112845 |
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Aug 2012 |
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WO |
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Other References
Italian Search Report issued in connection with corresponding
application CO2013A000060 dated Nov. 15, 2013. cited by applicant
.
International Search Report and Written Opinion issued in
connection with corresponding PCT application PCT/EP2014/074571
dated Nov. 14, 2014. cited by applicant.
|
Primary Examiner: Reid; Michael R
Attorney, Agent or Firm: GE Global Patent Operation
Claims
What is claimed is:
1. A control valve comprising: a cylindrical hollow trim defining
an inner bore extending along an axis between a first opening and a
second opening, the first opening defining an inlet of the valve,
the cylindrical hollow trim comprising: a first outer cylinder
extending along the axis and comprising a first plurality of radial
through holes defining an outlet of the trim, a second cylinder,
housed in the first cylinder and coaxial therewith, the second
cylinder comprising a second plurality of radial through holes; and
a plug sized to fit inside the bore and slidably movable along the
axis between a closed position proximal to the first opening and a
complete open position proximal to the second opening, through a
plurality of partially open positions, wherein in the complete open
position all the holes of the first and second plurality of through
holes are in communication with the inner bore and wherein in each
of the partially open positions only a respective portion of holes
of the first and second plurality of through holes are in
communication with the inner bore, wherein the holes of the first
plurality are smaller in diameter than the holes of the second
plurality, wherein the holes of the first plurality are in greater
number than the holes of the second plurality, and each hole of one
of the first and second cylinders of a projection along a radial
direction on the other of the first and second cylinders is spaced
from each hole of the other of the first and second plurality,
wherein the cylindrical hollow trim further comprises a plurality
of annular partition walls orthogonal to the axis and extending
through an annular space from one to the other of the first and
second cylinder in order to divide the trim into a plurality of
levels axially distributed along the axis between the first and
second openings, each of the levels defining one of the partially
open positions.
2. The control valve according to claim 1, wherein the cylindrical
hollow trim further comprises at least a third cylinder housed in
the second cylinder and coaxial therewith, the at least third
cylinder comprising a respective third plurality of radial through
holes, the holes of each couple of adjacent cylinders in the
cylindrical hollow trim being disposed in such a way that for each
hole of one of the adjacent cylinders of the projection along a
radial direction on the other of the adjacent cylinders is spaced
from each hole of the plurality of holes on the other of the
adjacent cylinders.
3. The control valve according to claim 1, wherein the distance
between the centres of two holes of the first plurality is greater
than 1.3d and lower than 3d, where d is the average diameter of the
holes of the first plurality.
4. The control valve according to claim 3, wherein the holes of the
first plurality have all the same diameter.
5. The control valve according to claim 1, wherein in each level
the total cross-sectional area of the holes of the first plurality
is greater than 1.1B and lower than 3B, where B is the total
cross-sectional area of the holes of the second plurality.
6. The control valve according to claim 2, wherein the distance
between the centres of two holes of the first plurality is greater
than 1.3d and lower than 3d, where d is the average diameter of the
holes of the first plurality.
Description
TECHNICAL FIELD
Embodiments of the present invention relate to a multistage control
valve.
BACKGROUND
State of the art of multistage trim for control valves has many
possible configurations. One of the most common types is composed
by concentric drilled hollow cylinders.
This type of trim has several solutions. In a solution, shown in
FIGS. 1A and 1B, the stroke is divided into separate axial levels.
A central plug slides inside the most inner cylinder from one axial
end, corresponding to the valve completely closed position, to the
opposite axial end, corresponding to the valve completely open
position, of the trim. Along its stroke, the plug progressively
opens in series the axial levels of the valve, from the first to
the last.
Another solution, is described in EP1408265. In this case, the
central plug slides inside the most inner cylinder progressively
opening a plurality of holes provided along the inner cylinder, an
annular plenum being provided between the inner cylinder and a
second outer cylinder provided with a second plurality of holes.
The annular plenum communicates with all the holes of the inner and
outer cylinders. Passing through the holes of the inner cylinder, a
gas expands in the annular plenum and then exit the trim by passing
through the holes in the outer cylinder.
Disadvantageous features of these solutions are, respectively to
keep the velocity of the fluid under certain limits as the gas
expands through the trim, the size of the holes must be increased
going from the inlet to the outlet cylinders. This increases the
noise at the last stage, corresponding to the most outer cylinder,
of the trim. As the plug slides the distribution of the pressure
drop among the stages is changed. In particular, at low valve
openings, the first stage is subject to very high pressure loss and
noise generation. In addition, the jets upstream of the last stage
are not fully deviated and masked.
Similar inconveniences are present also in the solutions described
in the documents CA1003727 and U.S. Pat. No. 4,617,963. It would be
therefore desirable to provide an improved valve for which could
maintain the advantages and avoid the inconveniences of both
solutions above.
SUMMARY
Such an object is achieved through a control valve comprising a
cylindrical hollow trim defining an inner bore extending along an
axis between a first opening and a second opening, the first
opening defining an inlet of the valve, the trim comprising a first
outer cylinder extending along the axis and comprising a first
plurality of radial through holes defining an outlet of the trim, a
second cylinder, housed in the first cylinder and coaxial
therewith, the second cylinder comprising a second plurality of
radial through holes, a plug sized to fit inside the bore and
slidably movable along the axis between a closed position proximal
to the first opening and a complete open position proximal to the
second opening, through a plurality of partially open positions,
wherein in the complete open position all the holes of the first
and second plurality of through holes are in communication with the
inner bore and wherein in each of the partially open positions only
a respective portion of holes of the first and second plurality of
through holes are in communication with the inner bore, wherein the
holes of the first plurality are smaller in diameter than the holes
of the second plurality, the holes of the first plurality are in
greater number than the holes of the second plurality, for each
hole of one of the first and second cylinders the projection along
a radial direction on the other of the first and second cylinders
is spaced from each hole of the other of the first and second
plurality.
The above solution permits to achieve the following advantages:
lower noise than the first prior art (FIGS. 1A and 1B) solution at
all flow regimes and lower noise than the second prior art
(EP1408265) solution at partial valve opening.
BRIEF DESCRIPTION OF THE DRAWINGS
Other object features and advantages of embodiments of the present
invention will become evident from the following description of the
embodiments of the invention taken in conjunction with the
following drawings, wherein:
FIGS. 1A and 1B are, respectively, an assonometric and a sectional
view of a component of a valve according to the prior art;
FIG. 2 is a sectional assonometric view of a valve according to the
present invention;
FIGS. 3A and 3B are, respectively, two sectional views of two
different embodiments of a component of the valve in FIG. 2.
FIGS. 4 and 5 are detailed views of the component in FIG. 3a.
DETAILED DESCRIPTION
With reference to first embodiment of the present invention (FIGS.
2, 3A, 4 and 5), a control multistage valve 1 comprises a
cylindrical hollow trim 2 extending along a longitudinal axis Y and
a plug 6 sized to fit inside the bore 5 and slidably movable along
the axis Y. The hollow trim 2 defines an inner bore 5 oriented
along the axis Y between a first circular opening 3 and a second
circular opening 4. The first opening 3 defines an inlet of the
valve 1. The trim 2 comprises a first outer cylinder 11 extending
along the axis Y and comprising a first plurality 14 of radial
through holes defining an outlet of the valve 1. The trim 2 also
comprises a second cylinder 12, housed in the first cylinder 11 and
coaxial with it. The second cylinder 12 comprises a second
plurality 15 of radial through holes.
The plug 6 slides between a closed position proximal to the first
opening 3 and a complete open position proximal to the second
opening 4, through a plurality of partially open positions. In the
complete open position all the holes of the first and second
plurality 14, 15 of through holes are in communication with the
inner bore 5. In each of the partially open positions only a
respective portion of holes of the first and second plurality 14,
15 of through holes are in communication with the inner bore 5.
The trim 2 further comprises a plurality of annular partition walls
20 orthogonal to the axis Y and extending through an annular
interspace 11 a from one to the other of the first and second
cylinder 11, 12 in order to divide the trim 2 into a plurality of
levels (nine levels 2A-I) in the embodiments of the attach FIG.
2-4) axially distributed along the axis Y between the first and
second openings 3, 4. Each level 2A-I comprises respective portions
of the first and second cylinder 11, 12 and respective portions of
the first and second plurality of holes 13, 14. Each of the levels
2A-I defines one of the partially open positions.
In the first embodiment of the present invention, the valve 1
comprises two stages and the trim 2 comprises exclusively the first
and the second cylinder 11, 12. When the valve 1 is fully or
partially open, i.e. when the plug 6 is remote from the first
opening 3, a fluid flows from the first opening 3 to at least part
of the levels 2A-I by reducing its energy pressure. Dividing the
trim 2 in several levels a more efficient reduction of pressure is
achieved as well as a reduction of noise. The fluid passes first
through the second inner cylinder 12 which constitutes a first
stage of pressure drop, then through the annular interspace 11A and
finally through the first outer cylinder 11 which constitutes a
second and last stage of pressure drop.
The holes of the first and second plurality 13, 14 are dimensioned
and positioned in such a way that: the first plurality 14 are
smaller in diameter than the holes of the second plurality 15, the
holes of the first plurality 14 are in greater number than the
holes of the second plurality, for each hole 14, 15 of one of the
first and second cylinders 11, 12 the projection along a radial
direction on the other of the first and second cylinders 12, 11 is
spaced from each hole 15, 14 of the other of the first and second
plurality of holes.
For the above configuration the holes of the first plurality 14 is
neither partially aligned, along a radial direction orthogonal to
the axis Y, with the holes of the second plurality 15.
The holes of the first and second plurality 13, 14 are further
dimensioned and positioned in such a way that: the distance 1
between the centres of two adjacent holes 14 of the first plurality
is comprised between 1.3D and 3D, where d is the average diameter
of the holes of the first plurality 14. In particular, according to
a possible embodiment of the present invention, the holes of the
first plurality 14 have all the same diameter d; in each level 2A-I
the total cross-sectional area A of the holes of the first
plurality 14 is comprised between 1.1B and 3B, where B is the total
cross-sectional area B of the holes of the second plurality of
holes 15.
In a second embodiment of the present invention (FIG. 3B), the
valve 1 comprises three stages and the trim 2 comprises also a
third cylinder 13 housed in the second cylinder 12 and coaxial with
it. The third cylinder 13 comprises a third plurality 16 of radial
through holes. Analogously to the first and second cylinder 11, 12,
also the holes of the couple of adjacent cylinders constituted by
the second and third cylinder 12, 13 are disposed in such a way
that for each hole of one of the second and third cylinders the
projection along a radial direction on the other of the second and
third cylinders is spaced from each hole of the other of the second
and third plurality of holes. The trim of the second embodiment
comprises a second annular interspace 12A from one to the other of
the second and third cylinder 12, 13.
In such second embodiment, fluid flows from the first opening 3 to
at least part of the levels 2A-I by reducing its energy pressure.
The fluid passes first through the third cylinder 13, which
constitutes a first stage of pressure drop, and then through the
second annular interspace 12A. From the second annular interspace
12A the fluid passes to the second inner cylinder 12 which
constitutes a second stage of pressure drop, then through the
annular interspace 11A and finally through the first outer cylinder
11 which constitutes a third and last stage of pressure drop.
According to other embodiments (not shown) the valve 1 comprises
four or more stages and the trim 2 comprises four or more cylinders
each corresponding to a respective stage of pressure drop.
In general, for all the embodiments, it however necessary that the
holes of the first and second plurality 13, 14 are further
dimensioned and positioned in such a way that the above conditions
a), b) and c) are fulfilled.
This written description uses examples to disclose the invention,
including the preferred embodiments, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *